Identify the wrongly matched pair.

Options

A. Free central placentation - Dianthus
B. Polyadelphous stamens - Citrus
C. Bilateral symmetry of flowers - Brassica
D. Standard petal of papillionaceous corolla - Vexillum

Answer

To identify the wrongly matched pair from the given options, we will analyze each pair one by one.

### Step 1: Analyze the first pair - Free central placentation in Dianthus
- **Explanation**: Free central placentation is a type of ovule arrangement where the ovules are attached to a central column. This is indeed found in the genus Dianthus.
- **Conclusion**: This pair is correctly matched.

### Step 2: Analyze the second pair - Polyadelphous stamen in Citrus
- **Explanation**: Polyadelphous stamen refers to a condition where stamens are grouped in bundles. Citrus plants exhibit this type of stamen arrangement.
- **Conclusion**: This pair is also correctly matched.

### Step 3: Analyze the third pair - Bilateral symmetry of flowers in Brassica
- **Explanation**: Brassica flowers typically exhibit radial symmetry, not bilateral symmetry. Radial symmetry means the flower can be divided into equal halves in multiple planes, while bilateral symmetry means it can only be divided into equal halves in one plane.
- **Conclusion**: This pair is wrongly matched.

### Step 4: Analyze the fourth pair - Standard petal of Papilionaceous corolla vexillum
- **Explanation**: In the Papilionaceous corolla (typical of the Fabaceae family), the standard petal (vexillum) is indeed the largest petal, with two smaller wings and a keel petal at the bottom. This matches the description.
- **Conclusion**: This pair is correctly matched.

### Final Conclusion
The wrongly matched pair is the third option: Brassica, which is said to have bilateral symmetry of flowers, but it actually has radial symmetry.

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